1. Field of the Invention
The present invention relates to a skin cleansing composition which can give an effective massaged feeling and has excellent cleanability.
2. Description of the Background Art
There are massaging compositions having as its objects the facilitation of the circulation of blood and the removal of an aged horny layer by the physical irritation of a scrubber, and detergent compositions having a physical cleansing effect that dirt or smears filled in pores of the skin are removed by a scrubber. The scrubber is generally composed of a water-insoluble substance such as a ground product of plant seeds, beads of a synthetic resin such as polyethylene, or an oily substance which is solid at an ordinary temperature, and is generally dispersed in a water-soluble base. However, such a water-insoluble scrubber has involved problems that it is poor in usability by reasons of difficult removal after use according to the particle diameter thereof and the like and that a sufficient massaging effect cannot be achieved.
In order to facilitate the removal after use, there has been proposed a granule-blended cosmetic composition in which granules of crystals of a saccharide or sugaralcohol, which is easily water-soluble, are dispersed in hydrophilic nonaqueous gel (Japanese Patent Application Laid-Open No. 17591911989. However, the composition is required to be washed out with a detergent or the like because it gives a feeling of remaining after use and is sticky to the feel.
It is an object of the present invention to provide a skin cleansing composition which can give an effective massaged feeling and has excellent cleanability.
The present inventors have found that a cleansing composition with a granulated product obtained by granulating particles of a specific surfactant with a binder incorporated into a substantially nonaqueous base can give an effective massaged feeling, and moreover has excellent cleanability and is easy to remove because the granulated product functions as a surfactant by physical disintegration or disintegration by contact with water, thus leading to completion of the present invention.
According to the present invention, there is provided a substantially nonaqueous skin cleansing composition comprising a granulated product obtained by granulating particles of a surfactant selected from the group consisting of nonionic surfactants, amphoteric surfactants and anionic surfactants with a binder.
The substantially nonaqueous skin cleansing composition according to the present invention scarcely causes damage to and itch on the skin, can give an effective massaged feeling and has excellent cleanability and no feeling of remaining after use.
The above and other objects, features and advantages of the present invention will be readily appreciated as the same becomes better understood from the preferred embodiments of the present invention, which will be described subsequently in detail, and from the appended claims.
As particles of the surfactant for forming the granulated product useful in the practice of the present invention, there may be used crystals or powder of a nonionic surfactant, amphoteric surfactant or anionic surfactant.
Examples of the nonionic surfactant include polyoxyethylene fatty acid esters, polyoxyethylene hardened castor oil, polyoxyethylene sorbitan fatty acid esters, glycerol fatty acid esters, polyoxyethylene alkyl ethers, polyoxyethylene polyoxypropylene glycol and alkylsaccharide type surfactants, with polyoxyethylene glycol monostearate,-polyoxyethylene lauryl ether, polyoxyethylene (160) polyoxypropylene (30) glycol, alkylpolyglycosides, etc. being particularly preferred.
Examples of the amphoteric surfactant include carbobetaine type surfactants, amidobetaine type surfactants, sulfobetaine type surfactants, phosphobetaine type surfactants, imidazolinium betaine type surfactants and amine oxide type surfactants, with fatty acid amide propylbetaines, alkylhydroxysulfobetaines, 2-alkyl-N-carboxymethyl-N-hydroxyethyl-imidazolinium betaines, alkyldimethylamine oxides, etc. being particularly preferred.
Examples of the anionic surfactant include higher fatty acid salts, polyoxyethylene alkyl ether sulfates, polyoxyethylene alkyl ether carboxylates, alkyl ether carboxylates, alkylsulfates, alkylbenzenesulfonates, higher fatty acid ester sulfonates, acylated isethionates, acylated amino acid salts, alkylisethionates, alkylphosphates, alkylsulfonates, N-acylamino acid salts, N-acyl-carboxyalkylglycine salts, N-alkylamidoalkanol sulfates and N-acyl-N-alkyltaurine salts. Of these, higher fatty acid salts, N-lauroyl-xcex2-alanine salts, monoalkylphosphates, higher fatty acid ester sulfonates, acylated isethionates, polyoxyethylene lauryl sulfates, lauryl sulfates, myristyl sulfates and polyoxyethylene laurylamide acetate are preferred.
Incidentally, as the salt used herein, is referred a salt with a metal such as potassium, sodium or magnesium, an ammonium salt, or an organic ammonium salt such as a monoethanol ammonium salt.
The particles of the surfactants are preferably those having a particle diameter of 0.01 to 1,000 xcexcm, particularly 0.01 to 700 xcexcm. The particles of the surfactants may be used either singly or in any combination thereof and preferably comprise an anionic surfactant, particularly, a higher fatty acid sodium salt, potassium N-lauroyl-xcex2-alanine, sodium monoalkylphosphate or sodium coconut oil fatty acid ethyl ester sulfonate.
As the binder used for granulating the surfactant, a water-soluble or a water-insoluble binder is used.
No particular limitation is imposed on the water-soluble binder so far as it dissolves upon contact with water. Examples thereof include synthetic polymers such as polyvinyl alcohol derivatives, poly(meth)acrylic acid alkali salts, alkali salts of (meth)acrylic acid/(meth)acrylic ester copolymers, alkali salts of acrylic acid/maleic acid copolymers and polyvinyl pyrrolidone; semisynthetic polymers such as starch derivatives, ethyl cellulose, methyl cellulose, carboxymethyl cellulose and hydroxyalkyl cellulose; and natural polymers derived from starch, see weeds, plant mucilages, proteins, etc.
Examples of the water-insoluble binder include acetyl cellulose, nitrocellulose, bentonite, talc, kaolin, silica, calcium carbonate, titaniumoxide, silicic acid anhydride, hydroxycalcium apatite, pearly substance and vinyl acetate resins.
The water-soluble binder is preferred. as the binder, with a polyvinyl alcohol derivative, ethyl cellulose or methyl cellulose being particularly preferred.
The binders may be used either singly or in any combination thereof in a proportion of preferably 0.1 to 80 parts by weight, particularly 0.5 to 70 parts by weight per 100 parts by weight of the surfactant particles.
No particular limitation is imposed on a method for granulating the surfactant particles with the binder. For example, they can be prepared by following a granulation process such as rolling granulation, rolling fluidized granulation, fluidized bed granulation, agitated rolling granulation, melt granulation, extrusion granulation or spray granulation, or a coating process such as spray drying after mixing the surfactant particles and the binder or while mixing them.
Into the granulated product, may be incorporated an oily substance which is solid at an ordinary temperature, for example, sunflower oil, a vegetable oil such as olive oil, silicone oil, volatile silicone oil, hardened castor oil, and/or the like in addition to the surfactant particles and binder.
The particle diameter of the thus-obtained granulated product is preferably 10 to 10,000 xcexcm, particularly 100 to 5,000 xcexcm from the viewpoint of the massaging effect. The granulated product is preferably incorporated in a proportion of 0.5 to 60% by weight, particularly 1 to 40% by weight, more particularly 2 to 30% by weight based on the total weight of the composition.
The skin cleansing composition according to the present invention must be nonaqueous, i.e., is required to substantially contain no water. However, it is unavoidable that water is mixed into the composition to some extent when water is contained in raw materials used. The term xe2x80x9csubstantially nonaqueousxe2x80x9d as used in the present invention means that a water content in the composition is preferably 10% by weight or lower, particularly 7% by weight or lower.
The skin cleansing composition according to the present invention is prepared by incorporating the granulated product into a nonaqueous base. The nonaqueous base is preferably liquid at ordinary temperature and pressure. Examples thereof include ethylene glycol monoethyl ether (ethylcarbitol), isoprene glycol, hexylene glycol, 1,2-pentanediol, polyethylene glycol, dipropylene glycol, ethylene glycol monobutyl ether, ethylene glycol monoethyl ether, 1,3-butylene glycol, 2-ethyl-1,3-hexanediol, diethylene glycol, propylene glycol and tris(ethoxyethoxyethyl)phosphate, with diethylene glycol monoethyl ether, isoprene glycol, hexylene glycol, dipropylene glycol, 1,3-butylene glycol and tris(ethoxyethoxyethyl)phosphate being particularly preferred.
These bases may be used either singly or in any combination thereof and preferably incorporated in a proportion of 40 to 99.5 % by weight, particularly 60 to 99% by weight based on the total weight of the composition from the viewpoints of a feeling upon use and a massaging effect.
Into the skin cleansing composition according to the present invention, may be suitably incorporated surfactants, antioxidants, germicides, antiphlogistics, oily substances, medicinally-effective ingredients, cold sensation-imparting agents, preservatives, perfume bases; inorganic powder such as talc, kaolin. pearly substances, hydroxycalcium apatite, silica, calcium carbonate, titanium oxide and silicic acid anhydride; thickeners such as hydroxypropyl cellulose and polyvinyl pyrrolidone; etc. in addition to the above-described components.
When the water-soluble binder is used as the binder in the granulated product used in the present invention, the granulated product is disintegrated by contact with water. When the water-insoluble-binder is used on the other hand, the granulated product is disintegrated by physical force, i.e., massaging. In each case, the cleansing function by the surfactant particles is exhibited after the disintegration of the granulated product, and so excellent cleanability can be achieved.
When the granulated product is disintegrated by the physical force, an end point of massaging can be identified by the time the granulated product has been disintegrated, and so it is only necessary to wash out the composition by adding water after that.